Archives & Solar Eclipse 2012
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Solar Eclipse of 14 November 2012:
A nearly total Eclipse of the Sun occurred here in Whangarei on the above date. I observed the effect of the eclipse on Propagation on 30 metres.

My Antenna is a half wave dipole, 8 metres above ground. The receiver is an ICOM IC R75 HF communications receiver. Sound card software is Spectrum Lab V2.78 b17 by DL4YHF.

There are two folders of Grabs. The first is a number of 10 minute Grabs covering 1950UTC to 2300UTC on 14/11/2012. The second are 4 hour grabs and contain a lot of redunant content, but they cover the same period as above. The The doppler shift I observed is caused by the rapid degeneration of the F2 layer (the lower layer) as the ionisation radiation from the sun is cut off, causing the F2 layer to reform into the F layer, In this case because the F1 layer is still stable and reflecting signals, it is causing the “double vision effect”. The rapid change in altitude of the F2 layer causes the Doppler shift. A similar effect to the shockwave from a CME causing rapid movement downwards of the F layer causing Doppler shifts on HF signals. Unfortunately the signal I observed was not stable enough in frequency to tell which ray was the "normal" signal ray.

Similar effects have been observed on the AM Broadcast band where the D layer causes severe attenuation of the sky wave from transmitters during daylight hours. At the time of the eclipse the D layer disappears entirely and there is a sudden and short burst of DX AM Stations on the band. I have not observed this myself, but it is well documented. Unfortunately Solar Eclipses are few and far between in my neck of the woods!

The eclipse started at 2030UTC, and ended at 2230UTC. Partial Totality occurred at 2134 (My estimation), with 91% (reported) of the Sun disk covered. At this time it was impossible to read indoors without the lights turned on, and outdoors there was a strange "sunlit" twilight.